n.准备工作

The problems existed in over flow dam headworks were discussed, the improving standard was stated. Gate dam headworks were recommended. 论述了溢流坝渠首工程存在的问题、改造的设计标准、闸坝结合型式渠首工程的特点，设计中应注意的问题及实际工程运用效果。

He accomplished this by separating the project in to two main parts: the headwork and the irrigation system. 是迄今世界上唯一留存，年代最久远，且不断发挥作用的生态型无坝引水工程，景观非常奇特。

Shenzhen Headworks Welding Equipment Co., Ltd. is a modern high-tech enterprise specializing in R&D, manufacture, sales and service of welding & cutting equipment. 深圳市恒鑫胜焊接设备有限公司是一家集焊接切割设备研发、生产、销售和服务于一体的现代高科技民营企业。

Solid brass molded, ceramic headwork, PP knob, epoxy resin powder coating on the surface, strong acid and alkalis resistant and anti-rusty. 采用实验室专用化验龙头，阀体采用全铜铸模工艺制造，高强度陶瓷阀心，手柄为耐酸碱高强度聚炳烯材质，表面经环氧树脂粉末高温烧涂工艺处理，整体具备防酸碱及防锈特性。

Huang Jinchi, Wang Yangui, A Study on the Warping near Irrigation Headwork of the Lower Reach of Yellow River. International Journal of Sediment Research, Vol. 14, No. 2,1999. 王延贵、匡尚富、李希霞，渠道冲淤特性及灌溉方式对渠道冲淤的影响，国家自然科学基金资助项目交流讨论会，1999年12月。

This paper introduces the determination of the calculating formula of the empty-support distance of headwork in the tunnel with large sections by using the plate theory. 文章介绍了利用薄板理论确定大断面巷道掘进期间的空顶距计算公式。